OpenVZ Converting /vz Container from ext3 to ext4

I got this error: Storing /vz/private/1332441.tmp/root.hdd/DiskDescriptor.xml
Error in check_mount_restrictions (ploop.c:1536): The ploop image can not be used on ext3 or ext4 file system without extents
Failed to create image: Error in check_mount_restrictions (ploop.c:1536): The ploop image can not be used on ext3 or ext4 file system without extents [21]
Destroying container private area: /vz/private/1332441
Creation of container private area failed

Fix:

Stop virtualization services:

Code:

[root@pcs ~]# service vz stop

Code:

[root@pcs ~]# service parallels-server stop

Remove /vz/pfcache.hdd partition:

Code:

[root@pcs ~]# rm -rf /vz/pfcache.hdd

Unmount /vz/ partition:

Code:

[root@pcs ~]# umount /vz

Convert the file system:

Code:

[root@pcs ~]# tune2fs -O extents,uninit_bg,dir_index /dev/DEVICE_NAME

Code:

[root@pcs ~]# e2fsck -fDC0 /dev/DEVICE_NAME

(This command will ask if you would like to fix errors; press Y to continue.)